struts2 jpg文件上传失败 Content-Type not allowed
org.apache.struts2.interceptor.FileUploadInterceptor - Content-Type not allowed: upload "upload__75549ca5_1239ddc5ce6__8000_00000161.tmp" image/pjpeg

原有配置:用ext+struts2上传时一直显示进度条不消失：

<action name="xxxAction"
/>
<result>/welcome.jsp</result>
</action>

原因：ie会把 jpg、jpeg翻译成image/pjpeg，png翻译成image/x-png 。而火狐则很标准：jpg、jpeg翻译成image/jpeg，png翻译成image/png。

解决方法：

<param name="allowedTypes">
image/bmp,image/png,image/gif,image/jpeg,image/jpg,image/x-png, image/pjpeg
</param>